Electron discharge device



April 7, 1942. J. w. WEST 2,278,628

ELECTRON DISCHARGE DEVICE Filed June 28, 1941 '3 Sheets-Sheet 1 M/l/E/V70/? J. W. WE 57' .MMM

A T TORNEV April 7, 1942. .1. w. WEST 2,278,628

' ELECTRON DISCHARGE DEVICE Filed June 28, 1941 3 Sheets-Sheet 2nvvewron m WEST 8V April 7, 1942. J. w. WEST 2,278,62 8- ELECTRONDISCHARGE DEVICE Filed June 28, 1941 3 Sheets-Sheet 3 FIG. 4

C 3.9 3a: C 43 45 49 l 43 39 46' 1 4 :t 25 Q J INVENTOR By J. W. WESTATTORNEY Patented Apr. 7, 1942 ELECTRON DISCHARGE DEVICE John W. West,Woodside, N. Y., assignor to Bell Telephone Laboratories, Incorporated,New York, N. Y... a corporation of New York Application June 28, 1941,Serial No. 400,221

18 Claims. (c1. 250- -2 7.5)

"This invention relates to electron discharge devices and moreespecially to such devices of high power capacity employed in short-wavetransmission systems.

In discharge devices having a large power output of the order of 1kilowatt or more, the electron emitting source is usually in the form ofa plurality of tungsten filament sections or strands which are tensionedto maintainthe strands in uniform spaced relation to other electrodes inthe device.- Since the power output is dependent on the area of theelectrodes, and other electrical characteristics of the device limit thediameters of the electrodes, it is evident that as the power isincreased the length of the electrodes must be increased so that inorder to offset turbulence and oscillatory action in the emittingstrands a sturdier supporting structure must be provided to realize thehighest efliciency of the device.

An object of this invention is to increase the stability of theelectrode assembly in discharge devices. v 1

Another object of the invention is to insure constant space relationbetween the associated electrodes in the device.

A further object of the invention is to prevent shock and vibration fromdistorting the electrodes from their normal relation. 7

These objects are attained in accordance with one aspect of theinvention in an air-cooled type device comprising a glass enclosingvessel providedwith an anode of large surface area, which surrounds acentral standard supporting multiple filament sections or strands, and acontrol electrode positioned intermediate the' filament and the anode.The'filament assembly and the grid or control electrode are supported'bypairs of terminals sealed-to the opposite end of the vessel.

A feature of the invention relates to a filament assembly of ruggedconstruction having a cen-' tral skeleton column or pillar formed ofa'plurality of rods arranged in a cylindrical boundary rigidly securedat opposite ends to platforms, the platform at one end supporting atension unit from which a plurality of filament sections are suspendedand the platform at the other end forming the base support of theassembly. 1

A further feature of 'this assembly relates to a tie plate 'or trussmember intermediate the platforms of the pillar for reenforcingthepillar against vibration, warpage and displacement of the individualrods of the pillar.

Another feature of the invention relates to the direct coupling of themultiple filament-sections to conductors supported in the stem of thevessel. This arrangement includes channel conductors extending fromterminals in the'stem,

" the conductors having extensions in bisecting'or crossing relationadjacent the supporting platform and the filament support rods extendingthrough the platform being seated in the channel recesses of theconductors. This facilitates the mounting of the'filament assembly inthe axis of the vessel and insures a rigid connection of the filamentrods directly to the conductors.

Still another feature of the invention relates to the support of thegrid or control electrode in symmetrical relation to the filamentassembly and the anode. This is accomplished by coupling a split band orother embracing member to the grid structure and supporting the bandbyupright channel conductors extending from terminals in the stem.

' These and other features and advantages of this invention willbeapparent from the following detailed description taken in connectionwith the accompanying drawings in which:

Fig. 1.is a perspective view of an electron discharge deviceillustrating one embodiment of the invention with a portion of theenclosing vessel broken away to show the internal structural' elements;l s

Fig. 2 is a view in elevation of the device of Fig. 1, showing theenclosing electrodes broken away and various details of the assembly incross section to aid in comprehending the invention;

Fig. 3 is a plan view in cross section of the electrode assembly takenon the line 33 of Fig. 2 inthe direction of the arrow to illustrate therelative positions of the respective electrodes;

Fig. 4 is" an enlarged perspective view of the lower portion of thefilament assembly separate fromit's position in the enclosing vessel;

Fig. 5 is a plan view of the structure of Fig. 4 showing therelationship of the various elements of the filament assembly and thecontrol electrode; and

Fig. 6 is a plan View of the lower end of the filament assembly taken online G6 of Fig. 2 in the direction of the arrow to illustrate theposition of the crossing conductors which are directly connected to thefilament assembly.

' Referring to the drawings, an electron discharge device illustrativeof the various features of this invention comprisesa double-ended en:closing vessel ll) having a molded or pre-cast dish portion. ll fused tothe lower reduced end of the enclosing vessel, the stem being providedwith thimble type metallic terminal members I2, each thimble having arim of knife-edge formation hermetically sealed into the glass wallsurrounding an aperture in the dish stem II. A larger diameter thimbleterminal I3 is sealed to the reduced upper end of the vessel I coaxialwith the axis of the vessel. The dish stem II is provided with a centralsealing tip I4 through which the vessel is evacuated prior to sealing. Aplurality of rigid conductors are mounted in the hollow terminals I2 inthe stem, as shown in Figs. 1 and 2. These conductors are formed ofchannel-shaped members I5 and I6 for the filament assembly and I1 and I8for the grid assembly.

The filament assembly, which forms one of the features of thisinvention, comprises a superstructure of rigid construction involving acage or skeleton column or pillar formed of six rigid rods I 9 to 23,inclusive, arranged in the boundary of a cylinder and anchored at oneend in a lavite disc or platform base 25, or other ceramic materialhaving a high insulating property, by metallic eyelets secured in thedisc, the rods I9 and 22 extending beyond the opposite face of the disc.These rods are bent inwardly to a smaller diameter circumference a shortdistance beyond the platform and then extend vertically to a metallicdisc or platform 26, the rods being secured therein by metallic eyelets.A reenforcing truss member or tie disc 21 engages the rod beyond theinward bend thereof with the edges bent downwardly in contact with therod and welded thereto, the disc having a sexagonal configuration asshown in Fig. 5. The disc 21 offsets the tendency of the rod to vibrateand materially strengthens the pillar construction of the filamentassembly, and the platform anchors at both ends of the rods insure astrong and stable construction. A filament tensioning assembly ismounted on the top of the metallic disc 26 and comprises a central rod28 extending through the disc and having a bent portion welded to one ofthe pillar rods. The tension assembly includes a helical spring 29surrounding the rod 28, which is mounted between insulating buttons 30and 3|, the upper button 30 supporting a universally movable platform 32and the insulating button 3| being seated upon a bowed bimetalliccompensating element 33 which slidably fits over the central rod 28 .andis seated on the metallic disc or platform 26. This tension assemblyforms no part of the present invention since the structure is disclosedand claimed in Patent 1,927,084, dated September 19, 1933, to C. Depewand Patent 2,082,120 dated June 1, 1937, to V. L. Ronci. The universallymovable platform 32 carries a plurality of wire hooks 34, which aresuspended below the tension assembly, each terminating in a locking loop35 which engages the bight of a hairpin filament section 36, preferablyof tungsten. There are four filament sections disposed about thepillarassembly and the lower ends thereof are clamped in the bent ends 31 of aU-shaped wire member 38 welded to the rods I9 and 22 slightly below theinward bends thereof. The other ends of the filaments are clamped in thebent terminations of similar U-shaped wire members 39 positionedintermediate the rods 20 and 2I, 23 and 24, respectively, and supportedon the insulating platform 25 by rods 40, which pass through eyelets inthe platform and extend below the platform, as shown in Fig. 4. Thisarrangement distributes the various sections of the filament in [acircular boundary about the pillar construction and. facilitates thealignment of the filament section in a uniform boundary throughout theirlength.

The projection of rods I9, 22 and 40 below the platform 25 facilitatesthe direct connection of the filament sections in parallel to the twoterminal conductors I5 and I6 rojecting from the stem, the extensions ofthe rods I9 and 22 being seated in spaced positions in the recess of theangular channel extensions 4I and welded therein, and the longerextensions of the rods 40 being seated in the recess of the bentextension channel portion 42 of the conductor I5. The extensions 4I and42 of the conductors are in transverse or bisecting relation to eachother in different planes so that they line up with the extending rodsin the platform 25 and therefore not only are electrically connected tothe filament sections, but also rigidly support the whole filamentassembly, the extension M of the conductor I6 abutting against the lowersurface of the platform 25 and being seated rigidly thereon. Theportions of the rods extending below the platform 25 may be Welded inthe channel members to insure a rigid connection and avoid highresistance coupling. The transverse or crossing extensions of theconductors I5 and I6 are in bisecting relation in the axis of the vesseland therefore equalize the bending stresses act-' ing on the filamentassembly. In view of the reenforced construction of these conductors andtheir short length between the filament assembly and the terminals I2, arigid and efiicient superstructure is realized. Furthermore, eachfilament section is electrically connected to both conductors I5 and I6through the rods I 9, 22 and 40, so that the filament sections areuniformly heated in parallel, whereby temperature variation in thesections is eliminated and undue strain is removed.

A control electrode or grid surrounds the filament assembly and isformed of a plurality of upright rods 43 secured at the lower end to theinner surface of a metallic ring 44 and having a fine wire 45 helicallywound about the rods and welded thereto. The control electrode or gridis axially supported with respect to the filament assembly by a bi-partmember or collar formed of a pair of arcuate bands 46 and 41 adequatelysecured to the ring 44 and provided with outwardly extending ears or tabportions 48 and 49, respectively at opposite ends thereof. The ears ortab portions are equally spaced from each other on opposite sides of thegrid structure to form a slot or groove for the flattened ends of thestraight channel conductors I1 and I8, respectively, which are welded tothe extensions and rigidly support the grid structure coaxially withrespect to the filament assembly.

A cylindrical anode 50 coaxially surrounds the filament assembly andgrid structure and is fabricated from a plurality of arcuate sheet metalsections having longitudinal flanges mechanically secured to adjacentflanges to constitute a cylinder, the flanges aiding in dissipating theheat generated in the anode and the arcuate sections being reenforced bycorrugations to prevent warping or buckling of the anode sections. Theanode is rigidly supported from the hollow terminal I3 on the top of thevessel ID by a tubular metallic member 5I rigidly seated in the terminalI3 and extending within the vessel I0, the tubular member 5I beingprovided with a ring flange 52. The cylindrical anode 50 is secured tothe flange 52 by a plurality of'pairs of bent wires 53 which are weldedto the lower face of the flange 52 at one end and secured to the outersurface on opposite sides of the spaced flangesaround the anode. Agetter support 54is mounted in the stem ll of the vessel and attached tothe conductor I whereby the residual gases remaining after the usualevacuation process is performed may be absorbed and localized in thedevice. The rugged construction of the electrode elements entering intothe assembly of the device enables the attainment of high operatingefficiency in power output and the individual supporting assemblies ofthe elements insure high insulation and. low internal resistance for theelements, particularly for operation in the ultra-high frequency rangein transmitting energy for communication systems.

While the invention has been described with respect to a particularembodiment of the invention, it is, of course, understood that variousmodifications may be made in the detailed assembly of the elements andtheir fabrication without departing from the spirit of the invention asdefined in the appended claims.

What is claimed is:

1. An electron discharge device comprising an enclosing vessel, aplurality of electrodeswithin said vessel including a cathode assembly,a pair of rigid conductors extending into said vessel and mounted inbisecting and insulating relation, and

means connecting said cathode assembly directly to said conductors. I

2. An electron discharge device comprising an enclosing vessel, aplurality of electrodes within said vessel including a cathode assemblyhaving a plurality of sections, a platform supporting said sections, apair of rigid conductors extending into said vessel and mounted inbisecting and insulating relation at one end of said vessel, and meansextending beyond said platform connecting said sections directly to saidconductors.

3. An electron discharge device comprising an enclosing vessel, aplurality of electrodes within said vessel including a cathode assemblyhaving a plurality of sections, a platform supporting said sections, apair of channel conductors extending into said vessel having portions inbisecting relation adjacent said platform, and connecting members forsaid sections extending on opposite sides of said platform and beingseated in the recesses of said conductors.

4. An electron discharge device comprising an enclosing vessel, aplurality of electrodes within said vessel including a cathode assemblyhaving a plurality of sections, a platform supporting said sections, anda pair of channel conductors extending into said vessel having portionsin bisecting relation, said platform abutting against one of saidportions and being joined to the other portion.

5. An electron discharge device comprising an enclosing vessel, aplurality of electrodes within said vessel including a cathode assemblyhaving a plurality of sections, a platform supporting said sections, anda pair of channel conductors extending into said vessel having portionsin bisecting relation, said platform being supported on one of saidconductors in one plane and being supported by the other conductor in atransverse plane.

6. An electron discharge device comprising a vessel containing aplurality of electrodes and having a molded dish stem at one end, hollowterminals sealed in said stem, channel-shaped conductors supported bysaid terminals, at least two .of said conductors having bent extensionscrossing at the axis of said vessel indifferent planes, a filamentassembly including an insulating platform, and supporting membersextending through said platform, certain of said supporting membersbeing joined to said channelshaped conductors in alignment therewith.

7. An electron discharge device comprising an enclosing vessel, aplurality of electrodes within said vessel including a filament assemblyformed of a plurality of incandescent sections disposed about a skeletonpillar support, said support having a plurality of upright rodsconnected together at opposite ends by support platforms, means on oneof said platforms engaging said sections, means onthe other platformsecuring the ends of said sections thereto, and strengthening meansengaging said rods intermediate said platforms to lessen the vibrationofv said rods.

8. An electron discharge device comprising an enclosing vessel, aplurality of electrodes within said vessel including a filament assemblyformed of a plurality of incandescent sections disposed about a skeletonpillar support, said support having a plurality of upright rodsconnected together at opposite ends by support platforms, means .on oneof said platforms engaging said sections, means onthe other platformsecuring the ends of said sections thereto, and a tie plate extendingacross said rods intermediate said platforms.

9. An electron discharge device comprising an enclosing vessel, aplurality of electrodes within said vessel including a filament assemblyformed of a plurality of incandescent sections disposed about a skeletonpillar support, said support having a plurality of upright rodsconnected together at opposite ends by support platforms, means on oneof said platforms engaging said sections, means on the other platformsecuring the ends of said sections thereto, and an apertured metallicdisc embracing said rods and extending in parbetween said platforms, theedge of said disc being flattened adjacent each rod.

11. A filament assembly for an electron discharge device comprising askeleton framework of upright rods mounted in a cylindricalconfiguration, a metallic plate secured to said rods at one end, aninsulating platform secured to said rods at the other end, a centralpost extending through said plate, a tension mounting surrounding saidpost, a plurality of filament sections surrounding said framework andbeing suspended from said mounting, and U-shaped anchors secured to saidrods adjacent said platform for receiving the free ends of said filamentsections.

12. A filament assembly for an electron discharge device comprising askeleton framework of upright rods mounted in a cylindricalconfiguration, a metallic plate secured to said rods at one end, aninsulating platform secured to said rods at the other end, a centralpost extending through said plate, a tension mounting surrounding saidpost, a plurality of filament sections surrounding said framework andbeing suspended from said mounting, U-shaped anchors secured to saidrods adjacent said platforms for receiving the free ends of saidfilament sections, and a metallic truss member reenforcing saidframework beyond the ends of said anchors.

13. A filament assembly for an electron discharge device comprising askeleton framework of upright rods mounted in a cylindricalconfiguration, a metallic plate secured to said rods at one end, aninsulating platform secured to said rods at the other end, a centralpost extending through said plate, a tension mounting surrounding saidpost, a plurality of filament sections surrounding said framework andbeing suspended from said mounting, U-shaped anchors secured to saidrods adjacent said platform for receiving the free ends of said filamentsections, and a metallic truss member reenforcing said framework beyondthe ends of said anchors, said truss member having overhanging portionsexterior to said rods and welded to the outer surfaces of said rods.

14. A filament assembly for an electron discharge device comprising askeleton framework of upright rods mounted in a cylindricalconfiguration, a metallic plate secured to said rods at one end, aninsulating platform secured to said rods at the other end, a centralpost extending through said plate, a tension mounting surrounding saidpost, a plurality of filament sections surrounding said framework andbeing suspended from said mounting, U-shaped anchors secured to saidrods adjacent said platform for receiving the free ends of said filamentsections, and auxiliary filament supports projecting from said platformparallel to said framework and positioned intermediate pairs ofoppositely disposed rods, said auxiliary supports having long extensionsprojecting from the opposite side of said platform.

15. In an electron discharge device having a dish stem provided withtubular metallic terminals projecting therefrom, a control electrodecomprising a plurality of upright support members, a helical wire woundabout said upright members, a ring attached to one end of said members,a pair of arcuate bands embracing said ring and having parallellyextending arms disposed on opposite sides of said ring, and rigidconductors directly connected to said terminals and secured between saidarms.

16. In an electron discharge device having a dish stem, provided withtubular metallic terminals projecting therefrom, a control electrodecomprising a plurality of upright supporting members, a helical wirewound about said upright members, a ring attached to one end of saidmembers, a pair of arcuate bands embracing said ring and havingparallelly extending arms disposed on opposite sides of said ring, andchannelshaped members extending vertically between said terminals andsaid bands and having compressed portions seated between said arms.

17. In an electron discharge device having a dish stem, a controlelectrode comprising a plurality of upright supporting members, ahelical wire wound about said upright members, a pair of arcuate bandssurrounding and connected to said members and having parallellyextending arms disposed on opposite sides thereof, a pair of tubularterminals sealed in said dish stem, said arms being in aligmnent withsaid terminals, and channel-shaped metallic conductors interconnectingsaid arms and said terminals, the ends of said conductors being seatedbetween said arms and in said terminals respectively.

18. An electron discharge device comprising an enclosing vessel having amolded dish stem, a plurality of hollow metallic terminals sealed insaid stem, a channel-shaped conductor extending into said vessel fromeach terminal, two of said conductors having portions bent at angleswhich cross each other in diametrical directions transverse to the axisof said vessel, the crossing point being coincident with said axis, anelongated pillar support extending coaxially within said vessel,extensions on said support, separately engaging the crossing portions ofsaid conductors, a plurality of filament sections surrounding andsupported by said pillar support, said sections being connected to saidextensions, a helical gridsurrounding said filament sections, a bipartcollar connected to one end of said grid, 2. pair of said conductorsbeing attached to said collar on opposite sides thereof, a cylindricalanode surrounding said grid, and a terminal support at the other end ofsaid vessel connected to said anode.

JOHN W. WEST.

